In Reply to: Why using line stage........ posted by bouncy ball on October 2, 2003 at 08:54:24:
IMO dynamics come from appropriate gain and correct impedance matching.
With today's 2 V CD outputs, resistive passive preamps can output enough voltage to saturate the power amp's inputs (so their gai structure is OK), however, they usually have high output impedance.One can make the analogy that passive preamps do not have the torque to rev up the engine, but given enough time will reach high RPMs (loudness).
What one neeeds is some means to lower the output impedance to enable the output stage to sink current(torque) and voltage(speed) into the power amp input.
There are two ways to accomplish this: a low impedance ative line stage or a transformer volume control, which lowers impedance by a factor of 4 as it reduces gain by a factor of 2(do a search on TVC).
Passive preamps based on resistors, potentiometers or switched attenuators will usually have about 5 K output impedance, way too high to really make a 10 K power amp input jump up and shout.
I hope this helps
Carlos
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: Why using line stage........ - Carlos 10/6/0316:10:52 10/6/03 (5)
- Hi Carlos and cheap-Jack - bouncy ball 21:37:08 10/7/03 (4)
- Re: Hi Carlos and cheap-Jack - cheap-Jack 13:38:09 10/21/03 (0)
- Passive TVC et al.... - Thorsten 06:43:59 10/19/03 (1)
- Re: Passive TVC et al.... - cheap-Jack 07:22:43 10/22/03 (0)
- Re: Hi Carlos and cheap-Jack - Carlos 07:04:59 10/8/03 (0)